published_or_final_version / Public Administration / Master / Master of Social Sciences

Το αντικείμενο της παρούσας διπλωματικής εργασίας είναι η ανασκόπηση της διαδικασίας της ευθυγράμμισης ιατρικών εικόνων, οι εξέταση των λόγων που την καθιστούν απαραίτητη για την ιατρική κοινότητα και οι ιδιαιτερότητες των ιατρικών εικόνων που θέτουν το ζήτημα της αναγκαιότητας ελαστικών τροποποιήσεων. Αρχικά πραγματοποιείται η παρουσίαση των επικρατέστερων μεθόδων ευθυγράμμισης και των σταδίων υλοποίησής τους. Γίνεται σύγκριση των άκαμπτων και των ελαστικών μεθόδων, καθώς και προτείνονται ερευνητικές προοπτικές για τη βελτίωση των τεχνικών. Στην παρούσα εργασία δίνεται έμφαση στον ελαστικό μετασχηματισμό Thin Plate Splines, γίνεται ανάλυση του μαθηματικού μοντέλου υλοποίησής του και προτείνεται μία μέθοδος βελτίωσης για την αυτόματη επιλογή και αντιστοίχιση σημείων ελέγχου. Στη συνέχεια πραγματοποιείται υλοποίηση τρισδιάστατου αφινικού και ελαστικού μετασχηματισμού για την ευθυγράμμιση τεχνητών και κλινικών ιατρικών δεδομένων. Γίνεται ποιοτική και ποσοτική σύγκριση των αποτελεσμάτων και αξιολογείται η αποτελεσματικότητα των μεθόδων σε σχέση με τα χαρακτηριστικά των διαφορετικών δεδομένων που επεξεργάζονται και τον αριθμό των σημείων που επιλέγονται. Τα κριτήρια που χρησιμοποιούνται είναι ποιοτικά και ποσοτικά, και αφορούν την ποιότητα της ευθυγράμμισης καθώς και το χρόνο εκτέλεσης των αλγορίθμων. / The current diploma thesis deals with the image registration process for medical images. The reasons that make image registration necessary to the medical community are considered, as well as the particularities of the medical images that make elastic transformation an absolute requirement. As a first stage, a presentation of the predominant registration methods takes place. Non-rigid and rigid methods are compared, and prospects for the improvement of the methods are proposed. Emphasis is placed on the elastic transformation with the use of Thin Plate Splines, the mathematical model for its algorithm design is analyzed, and a method for its optimization based on automatic points correspondences is presented. 3D Affine and TPS registrations are applied on both artificial and clinical medical data. The registration results are evaluated by qualitative and quantitative criteria, and the effectiveness of the algorithms is compared through application on the different data types and control points selections. The registration is overall evaluated for effectiveness and execution time.

Η διατριβή σχετίζεται με την επεξεργασία ιατρικών εικόνων για την ευθυγράμμιση και σύντηξη αυτών αλλά και για την ανίχνευση παθολογικών δομών. / The thesis concerns with the medical image processing, for their registration and fusion and for the detection of pathological structures

The work covered in this thesis deals with the problem of automatically registering 3D images acquired from different medical imaging modalities. The approach taken is to develop generic measures of image registration derived from the co-occurence of values in the two images. The development of statistical alignment measures is reviewed. The registration problem is then expressed in terms of entropy and developed using tools from information theory. The problem of the optimization of the registration process in the different types of algorithms is identified as important and the power of Genetic Algorithms is applied. The application of image registration techniques, implemented during this thesis, in complex situations is evaluated. The cases of patients with brain ischemia and brain tumour residual disease are elaborated. This is accomplished with the formation of Groupwares where the tacit knowledge, owned by the individual specialists that take part in the collaboration, is exposed and made explicit in the process of the evaluation of the findings, provided by the fused images. This is performed in a high performance computer network that has been developed between the Department of Medicine and the University Hospital. / Η παρούσα εργασία ασχολείται με το πρόβλημα της αυτοματοποιημένης προσαρμογής και σύντηξης τρισδιάστατων απεικονίσεων από διαφορετικές ιατρικές απεικονιστικές μεθοδολογίες.

Magistrantūros studijų baigiamajame darbe nagrinėjami teisiniai aspektai registruojant infrastruktūros objektus kaip atskirus nekilnojamojo turto daiktus. Analizuojamos susidarančios esminės problemos teisiškai valdyti inžinerinius statinius. Patirtis ir anketinė apklausa specialistų, atliekančių inžinerinių objektų matavimus ir registravimą parodo, kad šiuo metu intensyviai Lietuvoje vyksta naujų bei senų infrastruktūros objektų rekonstravimas, panaudojant ir Europos sąjungos (ES) lėšas. Pagal atliktą apklausą nustatyti faktoriai, kurie turi neigiamą įtaką inžinerinių statinių kadastrinių matavimų kokybei ir registravimui. Nagrinėjami žemės ir kito nekilnojamojo turto teisės šaltiniai bei jų reguliuojamieji teisiniai santykiai, nekilnojamojo turto kadastras, registras, jo perleidimo sandoriai, valdymas naudojimasis, disponavimas juo, servitutas. / Graduate Studies final examined the work of the legal aspects of registration facilities as separate property items. Analyze the fundamental problems arising in the management of buildings and civil engineering works legally. Experience and questionnaire survey of specialists to carry out the objects of engineering measurements and record shows that at present Lithuania is intensely new and old infrastructure reconstruction, and the use of EU funds. According to a survey carried out to identify factors that have a negative impact on the engineering and cadastral measurements of the quality of registration. Description of sources of Land and Real estate Law; relations regalement by Land and Real estate Law, Cadastre of Real Estate, Register, agreements of its alienation, management, usage, disposition, servitute.

Geninių paukščių apskaitos buvo vykdomos 2007 – 2008 metais, kovo – gegužės mėnesiais. Siekiant, kad surinkti duomenys kuo tiksliau atspindėtų geninių paukščių populiacijų rūšinę ir kiekybinę sudėtį, maršrutai buvo planuojami skirtingose ekologiniu ir antropogeniniu poveikiu aplinkose. Tyrimams buvo pasirinktos 4 skirtingos vietos: Raseinių miškų urėdijos Paliepių girininkijai priklausantis Paliepių miškas, Vilniaus miškų urėdijai Lavoriškių girininkijai priklausantis Lavoriškių miškas, Ignalinos miškų urėdijai Kaltanėnų girininkijai priklausantis Pakretuonės miškas ir Vilniaus miesto Vingio parkas. Apskaitų metu iš viso buvo pastebėtos 7 geninių paukščių rūšys: didysis genys, vidutinis genys, mažasis genys, baltnugaris genys, tripirštis genys, juodoji meleta ir žalioji meleta. Didžiausias rūšių skaičius buvo užregistruotas Vingio parke. Dažniausiai sutinkami buvo didysis genys ir juodoji meleta. Didžiausiu vietinių populiacijų tankumu pasižymi didysis genys. Palyginus 2007 – 2008 metų duomenis, Geninių paukščių populiacijų gausa visose tirtose vietovėse didėjo, tačiau pokyčiai nėra statistiškai patikimi. Nustatyta, kad dažniausios geninių paukščių rūšies – didžiojo genio vietinių populiacijų tankumui didžiausią įtaką turi: pirmojo medžio ardo amžius, medyno medžių rūšių įvairovė ir negyvos medienos kiekis medynuose. / Registration of woodpecker was carried out from March to May in 2007-2008. For the purpose of getting the data which would be as accurate as possible from the aspect of the woodpecker population species and quantity, the routes were planned in the environments differing in ecological and anthropological effect. 4 different sites were chosen for the research: Paliepiai forest that belongs to Paliepiai forestry of Raseiniai forester’s district, Lavoriskes forest that belongs to Lavoriskes forestry of Vilnius forester’s district, Pakretuone forest that belongs to Kaltanenai forestry of Ignalina forester’s district and Vilnius city Vingis Park. During registration 7 species of woodpeckers were observed: great spotted woodpecker, middle spotted woodpecker, lesser spotted woodpecker, white – backed woodpecker, three – toed woodpecker, black woodpecker and green woodpecker. The largest number of species was registered in Vingis Park. The species that are found most often are the great spotted woodpecker and the black woodpecker. The great spotted woodpecker is known for the greatest density of local populations. By comparing the data of 2007-2008 the abundance of populations of woodpeckers increased in all the surveyed sites, however, the changes are not statistically reliable. It has been found out that the density of the most frequent species of woodpeckers, i.e. the great spotted woodpecker, is most influenced by the following factors: the age of the first layer of the tree... [to full text]

PURPOSE: Thermal ablation therapy is an emerging local cancer treatment to destroy cancer tissue using heat. However variations in blood flow and energy absorption rates make it extremely challenging to monitor thermal changes. Insufficient ablation may lead to recurrence of the cancer while excessive ablation may damage adjacent healthy tissues. Ultrasound could be a convenient and inexpensive imaging modality for real-time monitoring of the ablation. For the development and optimization of these methods, it is essential to have ground truth data and a reliable and quantitative validation technique before beginning clinical trials on humans. In this dissertation, my primary focus was to solve the image-to-physical space registration problem using stereotactic fiducials that provide accurate correlation of ultrasound and pathology (ground truth) images. METHOD: A previously developed validation test-bed prototype was evaluated using phantom experiments to identify the shortcomings and limitations. In order to develop an improved validation platform, a simulator was implemented for evaluating registration methods as well as different line fiducial structures. New fiducial line structures were proposed, and new methods were implemented to overcome the limitations of the old system. The new methods were then tested using simulation results and phantom studies. Phantom experiments were conducted to improve the visibility of fiducials, as well as the quality of acquired ultrasound and pathology image datasets. RESULTS: The new system outperforms the previous one in terms of accuracy, robustness, and simplicity. The new registration method is robust to missing fiducials. I also achieved complete fiducial visibility in all images. Enhancing the tissue fixation medium improved the ultrasound data quality. The quality of pathology images were improved by a new imaging method. Simulation results show improvement in pose recovery accuracy using my proposed fiducial structure. This was validated by phantom studies reducing spatial misalignment between the US and pathology image sets. CONCLUSION: A new generation of test-bed was developed that provides a reliable and quantitative validation technique for evaluating and optimizing ablation monitoring methods. / Thesis (Master, Computing) -- Queen's University, 2011-09-29 20:31:55.159

The delivery of land administration (LA) systems particularly in urban areas underpins housing, industry and infrastructure development as well as the smooth operation of land and credit markets. However, fragmentation of LA activities across several autonomous organizations generally impairs end to end business processes flow and delivery. To facilitate improved service of LA systems we suggest the end to end measurement and monitoring of their business processes across organizational boundaries. This study proposes a performance measurement system that can facilitate end to end measurement and comparison of cross organizational business processes (CBPs) in LA. The research, which is structured in 2 parts, is based on a multi site study of LA CBPs in 6 urban municipalities across Namibia, Zimbabwe and South Africa. First, a measurement instrument (scorecard) built on six key CBP performance measurement areas of quality and technological innovation (enablers of results), cost and time (measures of results) and customer satisfaction and society (measures of external success (or impact), is presented. To facilitate measurement across organizational boundaries, the proposed dimensions were embedded onto a multi level structural model that link process activities to sub processes and CBPs. For 5 of the 6 municipalities, a conventional case of subdivision of privately owned land within an established township was used to develop CBP descriptions and process models for each municipality. A comparison of CBP and sub process similarities between municipalities was then done using the similarity scenario degree. Our results showed similarities of over 60% for most CBPs while mixed values were obtained for sub processes. The similarity results were further used as a base for the construction of a business process reference model. The second part of the research tested the applicability of quality and time dimensions. Using the survey examination and approval and deeds examination and approval sub processes, the quality of submitted work was measured using performance indicators of process yield and rejection rates at 2 survey examination and 3 deeds registration sites. Our results showed that 80% and 60% of survey records submitted at both survey examination sites were rejected and returned backwards for corrections due to quality deficits. Based on our results, we conducted a root cause analysis at one of the survey examination sites to identify major contributors to lower process yield. In addition, we suggested numerous technological innovations to improve quality. Using the same sites, we then went on to measure and compare cycle times for cadastral survey examination and approval considering quality. Our results showed that 70% and 52% of survey records with good quality had approval times of 20 days or less for the first and second sites, respectively while only 32% and 18% of records with poor quality (for same sites) were approved within 60 days. Furthermore, shorter cycle times appeared to indicate lower process costs. After the separate analysis of the quality and time measurements, a global performance index that aggregates individual measures into a composite value was presented. Overall, the study has shown the potential of end to end CBP performance measurement in improving delivery and service of land administration in a holistic manner. The results are important for initiatives directed at integration and improvement of land administration operations. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

This thesis presents a technique for face recognition that is based on image registration. The image registration technique is based on finding a set of feature points in the two images and using these feature points for registration. This is done in four steps. In the first, images are filtered with the Mexican hat wavelet to obtain the feature point locations. In the second, the Zernike moments of neighbourhoods around the feature points are calculated and compared in the third step to establish correspondence between feature points in the two images and in the fourth the transformation parameters between images are obtained using an iterative weighted least squares technique. The face recognition technique consists of three parts, a training part, an image registration part and a post-processing part. During training a set of images are chosen as the training images and the Zernike moments for the feature points of the training images are obtained and stored. In the registration part, the transformation parameters to register the training images with the images under consideration are obtained. In the post-processing, these transformation parameters are used to determine whether a valid match is found or not. The performance of the proposed method is evaluated using various face databases and it is compared with the performance of existing techniques. Results indicate that the proposed technique gives excellent results for face recognition in conditions of varying pose, illumination, background and scale. These results are comparable to other well known face recognition techniques.

This study reports on the quantitative evaluation of a set of state-of-the-art feature detectors and descriptors in the context of repeat photography. Unlike most related work, the proposed study assesses the performance of feature detectors when intra-pair variations are uncontrolled and due to a variety of factors (landscape change, weather conditions, different acquisition sensors). There is no systematic way to model the factors inducing image change. The proposed evaluation is performed in the context of image matching, i.e. in conjunction with a descriptor and matching strategy. Thus, beyond just comparing the performance of these detectors and descriptors, we also examine the feasibility of feature-based matching on repeat photography. Our dataset consists of a set of repeat and historic images pairs that are representative for the database created by the Mountain Legacy Project www.mountainlegacy.ca. / Graduate